Lightning arrester

ABSTRACT

A high voltage lightning arrester including a hollow insulating housing, a plurality of nonlinear resistance elements and insulating means alternately arranged in a main column for carrying a compressive load thereon, and a plurality of spark gap assemblies mounted on the insulating means adjacent the main column, alternate ones of the insulating means extended in general parallelism and at an angle relative to the remainder thereof so that the spark gap assemblies are nonloaded and arranged in two auxiliary columns adjacent the main column with successive assemblies disposed in different ones of the auxiliary columns.

D United States Patent n113,602,762

[72] Inventor Stanley S. Ken-slaw, Jr. 2,881,362 4/1959 Kalb 315/36 X Milwaukee, Wis. 3,313,978 4/1967 Miller 315/36 [21] Appl. No. 31,817 3,412,273 11/1968 Kennox etal 315/36 X :iled d :P

FOREIGN PATENTS [4 1 atente ug. I [73] Asian MCGIWE E Company 894,537 4/1962 Great Bntam 315/36 Milwaukee, Wk. Primary ExaminerDavid Schonberg Continuation of application Ser. No. ,Assislant Examiner- Paul A. 'Sacher 660,658, Aug. 15, 1967, now Attorney-Charles A. Prudell [54] LIGHTNING ARRESTER l0 Claim, 3 Drawing Figs.

ABSTRACT: A high voltage lightning arrester including a hol- 313/238, low insulatinghousing, a plurality of nonlinear resistance ele- 3115/ 35 ments and insulating means alternately arranged in a main 1 .1 column for carrying a compressive load thereon, and a plurali- U ty of spark gap assemblies mounted on the insulating means Field Search 3 1 adjacent the main column alternate nes of the insulating 231.1, 243, 325, 238; 315/35, 36; 317/61 means extended in general parallelism and at an angle relative to the remainder thereof so that the spark gap assemblies are [56] Ram Cw nonloaded and arranged in two auxiliary columns adjacent the UNITED STATES PATENTS main column with successive assemblies disposed in different 2,542,805 2/1951 Fink ones of the auxiliary columns.

PATENTEDAUG31 m1 3.602162 SHEET 1 OF 2 2 I'll.

IM/EA/TQR. Stanley 5. Kers/z'aw, J5.

PATENTED M1631 197i SHEET 2 OF 2 Z/VVE/VT'OR. Stanley 5. Kara/ma, J2

LIGHTNING ARRESTER This is a continuation of application Ser. No. 660,658, filed Aug. I5, 1967, now abandoned.

BACKGROUND OF THE INVENTION This invention relates to high voltage lightning arresters. High voltage station-type lightning arresters generally include a number of series connected units whose number determines the voltage rating of the device, and each unit includes a plurality of series connected nonlinear resistance elements and spark gap assemblies. The nonlinear resistance elements and the spark gap assemblies in prior art station type lightning arrester units were generally arranged in a plurality of physically parallel, vertical columns in order to reduce the overall height of the lightening arrester assembly. Each column generally included mixed resistance elements and spark gap assemblies and each was generally subjected to an endwise compressive load to hold the column together and to promote current interchange. Because each of the columns in such prior art lightning arresters had to be substantially the same height, the resistance elements and spark gap assemblies has to be held to a relatively close tolerance. In addition, close tolerances were important to insure that the relatively fragile spark gap assemblies were not overloaded. Also, where different numbers of resistance elements and spark gap assemblies were employed in the different columns, it was necessary to provide spacer members to insure uniform column height.

It is an object of the invention to provide a plural column lightning arrester assembly wherein only the nonlinear resistance elements are subject to a compressive endwise load.

Another object of the invention is to provide a lightning arrester assembly wherein there is no need for close tolerances in the spark gap assemblies and nonlinear resistance elements.

SUMMARY OF THE INVENTION A protective device comprising a hollow insulating housing, a plurality of nonlinear resistance elements and insulating support elements disposed in a column within the housing and subject to an endwise load, and a plurality of spark gap assemblies mounted on the insulating support elements and adjacent the column in a spaced-apart unaligned relation and substantially free of the endwise load, the nonlinear resistance elements and spark gap assemblies being connected in a series circuit relation.

BRIEF DESCRIPTION OF THE DRAWING F IG. 1 is a side elevational view, with parts broken away, of the lightning arrester according to the instant invention;

FIG. 2 is a view taken along lines 22 of FIG. 1; and

FIG. 3 schematically illustrates the arrangement of elements in the lightning arrester shown in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT The lightning arrester 10, according to the instant invention, is shown to include a hollow, generally cylindrical housing 11 of a suitable insulating material, such as porcelain or glass, and which is closed at its upper and lower ends by conductive end fittings l2 and 13, respectively. As those skilled in the art will appreciate, each of the end fittings 12 and 13 may be provided with a recess (not shown) for receiving the ends of the insulating housing 11 and each may be affixed to its respective end in a sealing relation by means of a suitable cementing compound (not shown). The housing 11 is provided with a central bore 14 for receiving a lightning arrester unit 15 which includes a plurality of nonlinear resistance elements 16 and spark gap assemblies 17.

While the lightning arrester unit 15 is a complete unit in itself and may be used as such, those skilled in the art will appreciate that, in a high voltage station type arrester, a plurality of such units may be arranged in a series relation within an elongate housing and that a plurality of such housings may be physically connected by suitably joining the end fittings l2 and 13.

The resistance elements 16 may have a generally cylindrical configuration and may be composed of a material such as silicon carbide, which has a nonlinear voltage characteristic whereby it presents a low resistance to surge currents and a high resistance to the normal power current of the system. The elements 16 are coaxially arranged in a vertical column and are separated by insulating members 18 which may be composed of any suitable insulating material, such as porcelain. In addition, a conductive, metallic end plate 19 is disposed between each of the end faces of the elements 16 and the insulating members 18. The column of resistance elements 16, insulating members 18 and end plates 19 may be secured by means of insulating tie rods 20 which may be pinned at each end to one of a pair of annular insulating members 21 which in turn may be suitably joined to metallic end members 23. Prior to the pinning of the tie rods 20, the column of resistance elements 16 and insulating members 18 may be placed in endwise compression in any manner well known in the art.

A metallic compression spring 25 is disposed between the upper end cap 12 and the upper end member 23 to firmly hold the assembly against a spacer member 26 which is disposed between the lower end member 23 and the lower end cap 13 As those skilled in the art will appreciate, conductive shunt members (not shown) may interconnect the conductive end plates 19 at the upper and lower ends of the column with the upper and lower end caps 12 and 13, respectively, to shunt the spring 25 and the spacer member 26.

Each of the insulating members 18 provided with an integral, generally annular radial extension 28, each of which supports one of the spark gap assemblies 17. The insulating members 18 are so oriented that alternate gap assemblies 17 are disposed in one of a pair of vertical columns disposed adjacent to and supported by the main column of resistance elements 16 and insulating members 18. It can thus be seen that the spark gap assemblies 17 are cantilevered outwardly from the main column of resistance elements 16 and insulating members 18 to provide two columns of sparkgap assemblies adjacent the column of resistance elements 16. Thus, while three vertical columns are provided in the lightning arrester assembly 15 to reduce the overall height of the device, only the resistance elements 16 and insulating members 18 carry any of the compressive load. None of this mechanical load is applied to the relatively fragile spark gap assemblies 17.

In addition, the height of each of the resistance elements 16, the spark gap assemblies 17 and insulating members 18 need not be held to close tolerances to match the height of adjacent columns of elements as in the case of prior art lightning arresters where the elements were arranged in mixed columns. Also, because successive spark gap assemblies 17 are arrayed in a staggered relation in the alternate columns, as illustrated in FIGS. 1 and 2, the air within the housing 11 may be employed as insulation between the lower end of one spark gap assembly 17 and the upper end of the next succeeding assembly.

The details of the spark gap assemblies 17 form no part of the instant invention and, accordingly, will not be discussed in detail. As an example of a spark gap assembly which could be employed in the instant lightning arrester, reference is made to US Pat. No. 3,242,376, issued Mar. 22, 1966, and assigned to the assignee in the instant invention.

As seen particularly in FIGS. 2 and 3, an integral conductive arm 32 extends radially from the end plate 19 at the lower end of each valve block 16 for connection to a first strap member 33 which extends upwardly for engaging a second conductive strap member 34 which is connected to the upper end of the spark gap assembly 17 and which extends radially therefrom. A third conductive strap member 36 connects the lower end of each spark gap assembly 17 to the end plate 19 at the upper end of the next succeeding valve block 16.

In addition, each of the spark gap assemblies may be shunted by an elongate, rodlike grading resistor 38 which is mounted between upper and lower socket members 39 and 40. The upper socket 39 is carried by the radially extending second strap member 34, and the lower socket 40 is mounted on a radially extending conductive support member 42 which is carried at the lower end of a generally U-shaped extension 43 of the strap 36 which in turn extends downwardly through a central opening 44 in the insulating support portion 28.

In operation, the spark gap assemblies 17 normally isolate the line conductor 45 connected to the upper end cap 12 from the grounded lower end cap 13. Upon the occurrence of a voltage surge, however, the spark gap assemblies 17 break down and conduct surge current carried by the line conductor 45 to ground. Because of the nonlinear resistance characteristic of the elements 16, they readily pass the surge current and then restore the system to its normal operating condition after the voltage across the device has returned substantially to the line voltage of the system, by limiting the flow of current to a value which is insufficient to sustain the arcing in the spark gap assembly 17.

While only a single embodiment of the invention has been shown and described, and while the invention has been illustrated with respect to one particular type of valve block and spark gap assembly, it is not intended to be limited thereby but only by the scope of the appended claims.

I claim:

1. A lightning arrester comprising:

a hollow insulating housing;

a plurality of valve blocks and separating insulators alternately vertically stacked to form a valve block column within the housing;

means for compressing the valve block column; and

a plurality of spark gap assemblies mounted horizontally adjacent the valve block column with each spark gap assembly electrically connected between a different respective adjacent pair of said valve blocks to form a series connection of valve blocks and spark gap assemblies and with each vertically adjacent pair of spark gap assemblies mounted out of vertical alignment with each other by a selected circumferential distance about said valve block column.

2. A lightning arrester according to claim 1 wherein said spark gap assemblies form two vertical columns of spark gap assemblies horizontally adjacent the valve block column spaced apart by the selected circumferential distance.

3. A lightning arrester according to claim 2 wherein said spark gap assemblies are mounted on and horizontally offset from the valve block column to form the two vertical columns.

4. A lightning arrester according to claim 1 wherein said spark gap assemblies are each of a greater height than a valve block and an adjacent insulator in the valve block column.

5. A lightning arrester according to claim 1 wherein said spark gap assemblies are mounted on and horizontally ofi'set from the valve block column.

6. A lightning arrester according to claim 1 also comprising a plurality of grading resistors each connected in parallel with a respective spark gap assembly.

7. A lightning arrester comprising:

a hollow insulating housing;

a main column of valve blocks and separating insulators under compression;

a first and second auxiliary column of spark gap assemblies mounted within the housing adjacent the main column with each Spark gap assembly electrically connected in series with and mounted horizontally adjacent to and offset from a respective pair of valve blocks in the main column and with said spark gap assemblies alternately mounted in said first and second auxiliary columns.

8. A lightning arrester according to claim 7 wherein said spark gap assemblies are each of a greater height than a valve block and an adjacent insulator in the main column.

9. A lightning arrester according to claim 7 also comprising a plurality of grading resistors each connected in parallel with a respective spark gap assembly.

10. A lightning arrester according to claim 7 wherein said auxiliary columns are spaced apart from each other a selected circumferential distance about the main column. 

1. A lightning arrester comprising: a hollow insulating housing; a plurality of valve blocks and separating insulators alternately vertically stacked to form a valve block column within the housing; means for compressing the valve block column; and a plurality of spark gap assemblies mounted horizontally adjacent the valve block column with each spark gap assembly electrically connected between a different respective adjacent pair of said valve blocks to form a series connection of valve blocks and spark gap assemblies and with each vertically adjacent pair of spark gap assemblies mounted out of vertical alignment with each other by a selected circumferential distance about said valve block column.
 2. A lightning arrester according to claim 1 wherein said spark gap assemblies form two vertical columns of spark gap assemblies horizontally adjacent the valve block column spaced apart by the selected circumferential distance.
 3. A lightning arrester according to claim 2 wherein said spark gap assemblies are mounted on and horizontally offset from the valve block column to form the two vertical columns.
 4. A lightning arrester according to claim 1 wherein said spark gap assemblies Are each of a greater height than a valve block and an adjacent insulator in the valve block column.
 5. A lightning arrester according to claim 1 wherein said spark gap assemblies are mounted on and horizontally offset from the valve block column.
 6. A lightning arrester according to claim 1 also comprising a plurality of grading resistors each connected in parallel with a respective spark gap assembly.
 7. A lightning arrester comprising: a hollow insulating housing; a main column of valve blocks and separating insulators under compression; a first and second auxiliary column of spark gap assemblies mounted within the housing adjacent the main column with each spark gap assembly electrically connected in series with and mounted horizontally adjacent to and offset from a respective pair of valve blocks in the main column and with said spark gap assemblies alternately mounted in said first and second auxiliary columns.
 8. A lightning arrester according to claim 7 wherein said spark gap assemblies are each of a greater height than a valve block and an adjacent insulator in the main column.
 9. A lightning arrester according to claim 7 also comprising a plurality of grading resistors each connected in parallel with a respective spark gap assembly.
 10. A lightning arrester according to claim 7 wherein said auxiliary columns are spaced apart from each other a selected circumferential distance about the main column. 